Centering device for lens machinery



Dec. 11, 1934. B DRESCHER 1,984,121

CENTERING DEVICE FOR LENS MACHINERY Filed May 10, 1932 FIG. 2

THEODORE B. DRESCHER INVENTOR 4 FIG.6 FIG. 5

ATTORNEY Patented Dec. 11, 1934 UNITED STATES 1 PATENT OFFICE 1,984,121 OENTERING DEVICE FOR LENS MACHINERY Application May 10, 1932, Serial No. 610,428 '2 Claims. (01. 51-101 This invention is applicable to lens grinding and cutting machines and more particularly it has reference to machines which are adapted to grind the edges of lenses and the like or to cut lenses from blanks.

One of the objects of my invention is to provide a lens edging machine embodying means for determining the optical center of a. lens. A further object is to provide a lens edging machine having a work carriage provided with means for locating the optical center of a lens. Still another object is to provide a machine of the type described having mechanism for holding a lens to be operated upon and means associated with said mechanism for determining the optical center of the lens. These and other objects and advantages reside in certain novel features of construction, arrangement and combination of parts as will hereinafter be more fully described.

Referring to the drawing:

Fig. 1 is a view, partly in section, showing the application of my invention to a lens edging machine.

Fig. 2 is a top plan view of same.

Figs. 3 and 4 are front views of reticule plates.

Fig. 5 shows the field of view when the lens is not centered.

Fig. 6 shows the field of view whenthe lens is centered. I g

One embodiment of my invention is illustrated in the drawing wherein 10 indicates the base of a lens edging machine on which a grinding element 11 is rotatably mounted and adapted to be driven by any suitable means, not shown, all as is well known to those skilled in the art. Swingably mounted on base 10, by means of stub shafts 12, is a work-carriage indicated generally by 13. The carriage 13 comprises a casting 14 within which'is rotatably mounted shaft 15 carrying gear wheel 16 which cooperates with another driven wheel 17.

Projecting upwardly from casting 14 are the four spaced bearing members 18 within two of which the hollow shaft 19 is rotatably mounted and within the other two the hollow shaft 20 is rotatably mounted. Fixedly secured to shaft 19 is a gear wheel 21 which cooperates with a pinion 22 secured to shaft 15. The two collars 23 are fixedly secured to hollow shaft 19 and prevent axial or longitudinal movement of the shaft. Shaft 20 is driven by means of a gear wheel 24 which cooperates with a pinion 25 carried by shaft 15.

Projecting outwardly from one of the members 18 is a bracket 26 on which is pivotally mounted a lever 27 having a yoke 28 provided with two pins 29 which cooperate with groove 30 formed in collar 31 secured to shaft 20. One end of coil spring 32 is secured to lever 27while the other end of the spring is secured to a lug 33 attached to one of the members 18. It.will be apparent, therefore, that shaft 20 is mounted for axial or longitudinal movement and can be moved by means of lever 27 against the action of spring 32 to insert a lens L to be edged between the two shafts 19 and 20. A ring 34 of leather or any other suitable material provides a friction contact for holding the lens L in position.

Fixedly mounted within shaft 19 is the tube 35 carrying-a lens 36 and two glass disks 37 and 38, the former of which carries two crossed index lines 37' arranged as shown in Fig. 3. A tube 39, mounted within shaft 20, carries a glass disk 40 and a lens 41. Another tube 42 is slidably mounted in hollow shaft 20 and adapted tobe moved by means of a pin 43 which projects through a slot in shaft 20. Tube 42 carries a glass disk 44 on which are formed. two index lines 44 which serve as a. target as will hereinafter be explained. A suitable color filter 45 is also mounted in tube 42. Mounted on a member 18 by means of brackets 46 is a lamp house 47 carrying a light source 48. Mounted on a member 18, at the opposite side of the machine, by brackets 49 is a housing 50 in which are mounted a prism 51, a lens 52 and an ocular 53.

In operation, shaft 20 ismoved away from shaft 19 by lever 27 so that a lens L may be inserted be tween the two shafts. The operator sights through the ocular 53 and if the lensL is properly positioned the field of view appears as'shown in Fig. 6 and if the lens L is improperly positioned. the field of view appears as shown in Fig. 5. When the lens L is properly located the optical center of the lens L coincides with its geometrical or mechanical center. The light source 48 illuminates the target 44 and lenses 41, and 36 together with lens L cooperate to form an image of the target on disk 3'7 which carries cross lines 3'7. The prism and ocular are used for examining the disk 3'7 and superposed image of 44. It is necessary to adjust tube 42 in accordance with the dioptric power of the lens L which-is to be centered and edged.

From the foregoing it will be apparent .that I am able to attain the objects of my invention and provide a combined lens edging and centering machine which can be conveniently used. Under the generally prevailing practice the optical center is first determined by a separate device and indicated by an ink dot. The lens is then placed in a chuck on a work carriage on the edging machine so that the ink dot is located in the mechanical axis of the chuck. By means of my device, however, the optical center can be determined when the lens is being placed in the chuck of the edging machine. This afiords convenience of operation and eliminates trouble caused by obliterated ink dots.

Although I have shown my invention applied to a lens edging machine, my device can be equally well applied to a lens cutting machine. Thus the lens could be placed on the cutting machine, its optical center determined and the cutting operation effected with reference to the optical center. Various modifications can obviously be made without departing from the spirit of my inven tion. Thus, for example, the optical system could be modified and simplified.

I claim:

1. A machine for operating upon lenses having in combination means for holding a lens to be operated upon, said means comprising two cylindrical members one of which is movable relative to the other and optical means within said members for locating the lens so that its optical center will be positioned relative to the axis of said members.

2. A lens edging machine having in combination a grinding element, mechanism for rotatably holding a lens to be edged against said element and means structurally associated with and carried by said mechanism for locating the lens in said mechanism, said means comprising a target, a lens system and means for illuminating said target.

3. A lens edging machine having in combination a base, a grinding element mounted on said base, a work carriage movably mounted on said base, said base comprising bearing members, two hollow shafts rotatably mounted in said bearing members, said shafts being mounted in axial alignment, one of'said shafts being axially movable whereby a lens may be clamped between said shafts and an optical system mounted within said shafts for locating a lens clamped between said shafts.

4. A lens edging machine having in combination a grinding element, a work carriage movably mounted with respect to said element, said carriage comprising two rotatably mounted hollow shafts, said shafts being in axial alignment, one of said shafts being axially movable whereby a lens may be clamped between the shafts, and means associated with said carriage for locating the lens in said carriage, said means comprising lenses and targets positioned within said shafts, a light source at one end of one shaft and observing means at the opposite end of the other shaft, said observing means comprising a reflecting device and an ocular.

5. A lens edging machine having in combination a grinding element, a work carriage for rotatably holding a lens against said element, said carriage comprising bearing portions, cylindrical members rotatably mounted in said portions, means for relatively moving said members axially to clamp the lens therebetween and means within said members for locating the leris to bring its optical center into a predetermined relation to the axis of said members.

6. A lens edging machine having in combination a work carriage, two aligned cylindrical members rotatably mounted on said carriage, means for rotating said members, means for clamping a lens between said members, and an optical system within said members, the axis of said system being substantially coincident with the axis of said members.

7. A lens grinding machine having in combination a grinding element, mechanism for holding a lens in contact with said element, said mechanism comprising a plurality of tubular shaft members and means mounted within said members for determining when the optical center of the lens is coincident with the axis of said members.

THEODORE B. DRESCHER. 

